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Abstract:

An engine system for starting a gas turbine engine includes a starter
coupled to the gas turbine engine and configured to provide torque to the
gas turbine engine; and a controller coupled to the starter and
configured to evaluate an engine system parameter and to select from a
plurality of start modes for starting the gas turbine engine based on the
engine system parameter.

Claims:

1. An engine system for starting a gas turbine engine, comprising: a
starter coupled to the gas turbine engine and configured to provide
torque to the gas turbine engine; and a controller coupled to the starter
and configured to evaluate an engine system parameter and to select from
a plurality of start modes for starting the gas turbine engine based on
the engine system parameter.

2. The engine system of claim 1, wherein the plurality of start modes
includes a first assisted start mode and a windmill start mode.

3. The engine system of claim 2, wherein, in the windmill start mode, the
controller is configured to provide acceleration commands to the gas
turbine engine according to a first acceleration schedule, and wherein,
in the first assisted start mode, the controller is configured to provide
acceleration commands to the starter according to a second acceleration
schedule.

4. The engine system of claim 3, wherein the plurality of start modes
further includes a second assisted mode, and wherein, in the second
assisted start mode, the controller is configured to provide acceleration
commands to the starter according to a third acceleration schedule.

5. The engine system of claim 2, wherein the system parameter is engine
acceleration of the gas turbine engine.

6. The engine system of claim 5, wherein the controller is configured to
select the first assisted start mode at a first acceleration rate and the
windmill start mode at a second acceleration rate, the first acceleration
rate being greater than the second acceleration rate.

7. The engine system of claim 5, wherein the plurality of start modes
further includes a second assisted start mode, and wherein the controller
is configured to select the windmill start mode when the engine
acceleration is less than a first predetermined acceleration rate, the
first assisted start mode when the engine acceleration is greater than a
second predetermined acceleration rate, and the second assisted start
mode when the engine acceleration is greater than or equal to the first
predetermine acceleration rate and less than or equal to the second
predetermined acceleration rate.

8. The engine system of claim 1, wherein the system parameter is starter
condition that indicates an amount of torque assistance available to gas
turbine engine.

9. The engine system of claim 2, further comprising a fuel system
configured to deliver fuel to the gas turbine engine, and wherein, in the
windmill start mode, the controller is configured to provide fuel
commands to the fuel system according to a first fuel schedule, and
wherein, in the first assisted start mode, the controller is configured
to provide fuel commands to the fuel system according to a second fuel
schedule.

10. The engine system of claim 9, wherein the plurality of start modes
further includes a second assisted start mode, and wherein, in the second
assisted start mode, the controller is configured to provide fuel
commands to the fuel system according to a third fuel schedule.

11. A method for starting a gas turbine engine, comprising the steps of:
evaluating, with a controller, a condition of a starter coupled to the
gas turbine engine; selecting, with the controller, a start mode based on
the condition of the starter; and generating acceleration commands based
on the selected start mode.

12. The method of claim 11, wherein the selecting step includes selecting
between a first assisted start mode and a windmill start mode.

13. The method of claim 12, wherein the generating step includes
generating the acceleration commands for the gas turbine engine according
to a first acceleration schedule in the windmill start mode, generating
the acceleration commands for the starter according to a second
acceleration schedule in the first assisted start mode.

14. The method of claim 13, wherein the plurality of start modes further
includes a second assisted start mode, and wherein the generating step
further includes generating the acceleration commands for the starter
according to a third acceleration schedule in the second assisted start
mode.

15. The method of claim 12, wherein the evaluating step includes
evaluating engine acceleration of the gas turbine engine as an indication
of the condition of the starter.

16. The method of claim 15, wherein the selecting step includes selecting
the first assisted start mode at a first acceleration rate, and selecting
the windmill start mode at a second acceleration rate, the first
acceleration rate being greater than the second acceleration rate.

17. The method of claim 15, wherein the plurality of start modes further
includes a second assisted start mode, and wherein the selecting step
includes selecting the windmill start mode when the engine acceleration
is less than a first predetermined acceleration rate, selecting the first
assisted start mode when the engine acceleration is greater than a second
predetermined acceleration rate, and selecting the second assisted start
mode when the engine acceleration is greater than or equal to the first
predetermine acceleration rate and less than or equal to the second
predetermined acceleration rate.

18. The method of claim 12, further comprising the steps of generating,
in the windmill start mode, fuel commands for a fuel system configured to
deliver fuel to the gas turbine engine according to a first fuel
schedule, and generating, in the first assisted start mode, fuel commands
for the fuel system configured to deliver fuel to the gas turbine engine
according to a second fuel schedule.

19. The method of claim 18, wherein the plurality of start modes further
includes a second assisted start mode, and wherein the method further
comprises the step of generating, in the second assisted start mode, fuel
commands for the fuel system according to a third fuel schedule.

20. An engine system for starting a gas turbine engine, comprising: a
starter coupled to the gas turbine engine and configured to provide
torque to the gas turbine engine; a fuel system coupled to the gas
turbine engine and configured to provide fuel to the gas turbine engine;
and a controller coupled to the starter and the fuel system, the
controller being configured to determine an acceleration rate of the gas
turbine engine, select between an assisted start mode and a windmill
start mode based on the acceleration rate, and generate fuel commands for
the fuel system according to a first acceleration schedule in the
assisted start mode and according to a second acceleration schedule in
the windmill start mode.

Description:

TECHNICAL FIELD

[0001] The present invention generally relates to gas turbine engines, and
more specifically to engine systems and methods for controlling the gas
turbine engines during start operations.

BACKGROUND

[0002] In many aircraft, gas turbine engines perform a number of
functions, including providing propulsion for the aircraft and driving
various other rotating components such as, for example, generators,
compressors, and pumps, to thereby supply electrical and/or pneumatic
power. Such engines may be incorporated into auxiliary power units (APU)
that supplement main propulsion engines by providing electrical and/or
pneumatic power.

[0003] A gas turbine engine typically includes a compressor section, a
combustion section, and a turbine section. The compressor section
compresses air provided at a forward end of the gas turbine engine and
provides the compressed air to the combustor section. Fuel is added to
the compressed air, and the resulting mixture is ignited within the
combustion section to produce combustion gases. The combustion gases are
directed to the turbine section, which extracts energy from the
combustion gases to provide the motive force necessary to power the
compressor section and auxiliary components, such that the gas turbine
engine is self-sustaining.

[0004] In general, there are a number of ways to start the gas turbine
engine, referred to below as "start modes." In conventional aircraft, the
pilot selects the appropriate type of start mode. For example, one such
mode is an assisted start mode in which an electric or pneumatic starter
motor is used to initially provide a motive force to the shaft connecting
the compressor section to the turbine section. The starter motor may be
used to increase the speed of the compressor section to a point at which
the compressed air provided to the combustion section results in a
fuel/air mixture that is suitable for ignition (commonly referred to as
"light-off"). Following light-off, the starter motor is discontinued when
the gas turbine engine is self-sustaining (i.e., the power generated by
the turbine section is sufficient to power the compressor section) such
that the gas turbine engine does not require the motive force from the
starter motor. In other situations, the start mode may be a windmill
start mode in which the air flowing into the engine (as a result of
forward motion or forced induction) is used to drive the compressors. As
in the assisted start mode, the air flowing into the combustion section
is mixed with fuel and ignited. The decision about start mode depends on
a number of parameters and either mode may be more appropriate depending
on the scenario. Typically, the pilot performs a sequence of steps to
select the correct start mode. Inappropriate selection of start mode may
result in incomplete and/or delayed starts, and/or excessive engine
temperature conditions.

[0005] Accordingly, it is desirable to provide engine control systems that
start a gas turbine engine in a more automatic and autonomous manner,
particularly by providing selection of start mode by the engine control,
rather than by the pilot. Furthermore, other desirable features and
characteristics of the present invention will become apparent from the
subsequent detailed description of the invention and the appended claims,
taken in conjunction with the accompanying drawings and this background
of the invention.

BRIEF SUMMARY

[0006] In accordance with an exemplary embodiment, an engine system for
starting a gas turbine engine includes a starter coupled to the gas
turbine engine and configured to provide torque to the gas turbine
engine; and a controller coupled to the starter and configured to
evaluate an engine system parameter and to select from a plurality of
start modes for starting the gas turbine engine based on the engine
system parameter.

[0007] In accordance with another exemplary embodiment, a method is
provided for starting a gas turbine engine. The method includes
evaluating, with a controller, a condition of a starter coupled to the
gas turbine engine; selecting, with the controller, a start mode based on
the condition of the starter; and generating acceleration commands based
on the selected start mode.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will hereinafter be described in conjunction
with the following drawing figures, wherein like numerals denote like
elements, and

[0009]FIG. 1 is a schematic block diagram of an engine system in
accordance with an exemplary embodiment;

[0010] FIG. 2 is a flowchart depicting a method for starting the engine
system of FIG. 1 in accordance with an exemplary embodiment;

[0011]FIG. 3 is a chart depicting exemplary acceleration schedules for
the engine system of FIG. 1 in accordance with an exemplary embodiment;
and

[0012]FIG. 4 is a chart depicting exemplary fuel schedules for the engine
system of FIG. 1 in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

[0013] The following detailed description is merely exemplary in nature
and is not intended to limit the invention or the application and uses of
the invention. As used herein, the word "exemplary" means "serving as an
example, instance, or illustration." Thus, any embodiment described
herein as "exemplary" is not necessarily to be construed as preferred or
advantageous over other embodiments. All of the embodiments described
herein are exemplary embodiments provided to enable persons skilled in
the art to make or use the invention and not to limit the scope of the
invention which is defined by the claims. Furthermore, there is no
intention to be bound by any expressed or implied theory presented in the
preceding technical field, background, brief summary, or the following
detailed description.

[0014] Broadly, exemplary embodiments discussed herein provide engine
systems and methods associated with gas turbine engines. Particularly,
the engine system is directed to starting the engine in a more automatic
and autonomous manner. An engine controller may select the appropriate
start mode of the engine based on a system parameter, such as current
engine acceleration. For example, when the acceleration is greater than a
predetermined acceleration rate, the engine controller may start the
engine according to an assisted start mode in which the starter (or
starter generator) assists in driving the engine up to a sustainable
speed. As another example, when the acceleration is less than a
predetermined acceleration rate, the engine controller may start the
engine according to a windmill start mode in which the starter provided
very little or no assist in driving the engine. Each start mode may have
predetermined acceleration and fuel schedules.

[0015]FIG. 1 is a schematic representation of an exemplary aircraft
engine system 100. The engine system 100 generally includes a gas turbine
engine 110, a gearbox 130, a starter (or starter generator) 140, an
engine controller 150, and a fuel system 170.

[0016] Typically, the engine 110 includes a compressor section 112, a
combustion section 114, a turbine section 116, and a spool or shaft 118.
During a typical running operation, the compressor section 112 draws in
ambient air, compresses it, and directs it into a combustion section 114.
The combustion section 114 receives the compressed air, mixes it with
fuel from the fuel system 170, and ignites the resulting mixture to
generate high energy combustion gases, which are directed into the
turbine section 116. The high energy combustion gases expand through the
turbine section 116, which in turn, drives the shaft 118 to produce
mechanical power and/or electrical power. The gearbox 130 is coupled to
the shaft 118 and provides or receives the mechanical energy from the
shaft 118, various accessories, and the starter 140 as described below.
The combusted gases exiting the turbine may be exhausted through an
exhaust system (not shown). The schematic representation in FIG. 1 is
merely one exemplary engine configuration, and the exemplary embodiments
discussed herein are applicable to other types of configurations.

[0017] The engine 110 may be, for example, an auxiliary power unit (APU),
although the engine system 100 described herein are also applicable to
other types of engines, including propulsion engines. As described below,
the engine 110 may further include any number of sensors for measuring
engine characteristics, including an acceleration (or speed) sensor 120
for measuring or deriving the acceleration of some aspect of the engine,
such as the shaft 118 or a rotor. In one exemplary embodiment, the system
120 may be located in the gearbox 130.

[0018] As noted above, the fuel system 170 is configured to deliver a flow
of fuel to the combustion section 114 of the engine 110. As such, the
fuel system 170 may include a tank or other source of fuel, valves,
pumps, nozzles, and the like for providing a designated volume and rate
of fuel.

[0019] The engine controller 150 generally controls the overall operation
of the engine 110 as well as the fuel system 170. More specifically, the
engine controller 150 receives signals from various sensors and systems
and, in response to these signals, controls the engine 110 during
start-up, operation, and shut-down. As examples, included among the
signals supplied to the engine controller 150 may include speed or
acceleration signals from sensor 120; an exhaust gas temperature (EGT)
signal; and/or a fuel flow signal from the fuel system 170. The engine
controller 150 may also receive external sensor signals from other
sources, including signals such as the altitude of the aircraft and the
ambient and/or total temperature. In response to these signals, the
engine controller 150 provides command signals to various components,
including the engine 110, the starter 140 and the fuel system 170.
Additional details about operation of the engine controller 150 during
start modes will be discussed below after a brief description of the
other components of the engine system 100.

[0020] The starter 140 is coupled to the engine 110 through the gearbox
130. In one exemplary embodiment, the starter 140 is an electric starter
and receives electrical power from an external power source, such as a
battery or other AC or DC power source. In another exemplary embodiment,
the starter is a pneumatically driven starter, and receives pneumatic
power from an external power source, such as an APU or another engine.

[0021] In addition to coupling the starter 140 to the engine 110, the
gearbox 130 may also drive mechanical accessories such as tachometers,
generators or alternators, hydraulic pumps, fuel pumps, oil pumps, fuel
controls, and water pumps with power from the engine 110 or starter 140.
The gearbox 130 may include any number of gears, shafts, and clutches for
transferring energy between the engine 110, starter 140, and the other
accessories. As an example, the gearbox 130 may provide mechanical power
to the fuel system 170.

[0022] The manner in which the engine controller 150 operates to control
the engine 110 during start-up, operation, and shut-down may vary
according to control logic stored in memory. In particular, and as will
be described in more detail, the engine controller 150 provides command
signals to the starter 140, engine 110, and the fuel system 170 according
to the control logic.

[0023] As described below, the engine controller 150 may select the
appropriate start mode of the engine 110, and exemplary modes may include
a first assisted start mode, a second assisted start mode, and/or a
windmill start mode. The start modes are introduced below prior to a more
detailed description.

[0024] In the windmill start mode, the ram air and air entering the engine
as a result of forward airspeed drive the engine 110. The engine
controller 150 generates acceleration commands for the engine 110 and
fuel commands for the fuel system 170 to deliver a designated amount of
fuel to the engine 110 according to predetermined acceleration and fuel
schedules. Typically, the windmill start mode does not involve mechanical
assistance. In general, the windmill start mode requires sufficient
aircraft forward airspeed to provide the aerodynamic assistance required
for starting the engine. Accordingly, at low aircraft airspeeds, an
attempted start in windmill start mode may result in undesirable issues,
such as incomplete and/or delayed starts, and/or excessive engine
temperature conditions. The windmill start mode is most appropriate when
the starter 140 is unavailable and/or does not have sufficient capability
to assist in driving the engine 110.

[0025] In the first and second assisted start modes, the engine controller
150 generates acceleration commands to drive the engine 110 and fuel
commands for the fuel system 170 to deliver a designated amount of fuel
to the engine 110 according to predetermined acceleration and fuel
schedules. The first and second assisted start modes generally provide
faster starts than the windmill start mode and are necessary when the
airspeed of the aircraft is insufficient for the windmill start mode,
e.g., when the aircraft is on the ground. The first assisted start mode
is most appropriate when the starter 140 is capable of providing the
highest level of torque desired by the engine 110. The second assisted
start mode is most appropriate when the starter 140 is able to provide
some torque but not the highest level that would otherwise be desired by
the engine 110. Additional details about the start-up operation will be
provided below with reference to FIG. 2.

[0026] FIG. 2 is a flowchart depicting a method 200 for starting an engine
system in accordance with an exemplary embodiment. In one exemplary
embodiment, the method 200 may be associated with the engine system 100
of FIG. 1. As such, FIG. 1 will be referenced below.

[0027] In a first step 205, a pilot initiates starting the engine 110,
e.g., at a user interface in the cockpit. Typically, the pilot initiates
a generic start operation and does not select a particular start mode.

[0028] In a second step 210, the engine controller 150 provides a command
to the starter to assist the engine starting with the energy available or
controlled to it. Any suitable start schedule may be used by the
controller 150 in step 210.

[0029] In a third step 215, the engine controller 150 evaluates a system
parameter. In general, the system parameter provides an indication of the
current capability of the starter 140 to provide a sufficient amount of
torque assistance to the engine 110. In one exemplary embodiment, the
system parameter is engine acceleration. Engine acceleration (or speed)
data may be provided by the sensor 120 within or proximate to the engine
110.

[0030] Depending on the speed or acceleration rate, the method 200
proceeds to steps 220, 230, or 240. In alternate embodiments, other
system parameters may be used to evaluate the starter 140 assistance
level. For example, the position of pneumatically activated valves may
indicate the amount of pressure in a pneumatic starter , and thus, the
level of available assistance. Other indications of starting assistance
level available or being used could include starter electrical current,
starter electrical voltage, or starter pressure levels. In some
situations, more than one parameter may be used, such as the position of
the value and acceleration. In the description below, acceleration is
evaluated as the system parameter, although analogous methods may use
other parameters or combinations of parameters.

[0031] If the acceleration rate is less than a first predetermined rate,
the method 200 proceeds to step 220 in which the engine controller 150
initiates an engine start in windmill start mode. This level of
acceleration indicates that the starter 140 may be unable to provide
torque assistance. In step 225, the engine controller 150 provides
acceleration and fuel commands to the engine 110 and fuel system 170,
respectively, according to a first acceleration schedule and a first fuel
schedule. Additional details about the acceleration and fuel schedules
are provided below. In general, the windmill start mode continues until
the engine 110 is ignited and reaches a predetermined, self-sustaining
engine speed and/or an engine speed of 100%.

[0032] In step 215, if the acceleration rate is greater than a second
predetermined rate, the method 200 proceeds to step 230 in which the
engine controller 150 initiates an engine start in a first assisted start
mode. This level of acceleration indicates that the starter 140 may be
able to provide full torque assistance. In step 235, the engine
controller 150 provides acceleration and fuel commands to the starter 140
and fuel system 170, respectively, according to a second acceleration
schedule and a second fuel schedule. Additional details about the
acceleration and fuel schedules are provided below. In general, the first
assisted start mode continues until the engine 110 is ignited and reaches
a predetermined, self-sustaining engine speed and/or an engine speed of
100%.

[0033] In step 215, if the acceleration rate is greater than or equal to
the first predetermined rate and less than or equal to the second
predetermined rate, the method 200 proceeds to step 240 in which the
engine controller 150 initiates an engine start in a second assisted
start mode. This level of acceleration indicates that the starter 140 may
be able to provide partial torque assistance. In step 245, the engine
controller 150 provides acceleration and fuel commands to the starter 140
and fuel system 170, respectively, according to a third acceleration
schedule and a third fuel schedule. Additional details about the
acceleration and fuel schedules are provided below. In general, the
second assisted start mode continues until the engine 110 is ignited and
reaches a predetermined, self-sustaining engine speed and/or an engine
speed of 100%.

[0034] As noted above, if available, other indications of available
starter assistance may be used in addition to or in place of
acceleration. For example, if starter voltage is below a first
predetermined value in step 215, the method 200 may proceed to step 220;
if greater than a second predetermined value, to step 240; and if between
the first and second predetermined values, to step 230. Additionally,
acceleration and fuel schedules are discussed above, and below, as
mechanisms for controlling the starter 140 and the engine 110. However,
any suitable control technique may be used in the system 100 and method
200 described herein, including acceleration schedules, fuel flow/burner
pressure schedules, fuel flow schedules, and the like.

[0035]FIG. 3 is a chart 300 depicting exemplary acceleration schedules
for the engine system 110 of FIG. 1 in accordance with an exemplary
embodiment. Chart 300 represents the acceleration rate command as a
function of engine rotor speed (in %/sec2). As noted above, one
exemplary schedule uses acceleration, although any suitable engine
starting schedules may be used those expressed in raw measurements or
"nondimensional" buckingham-pi corrected units, e.g., corrected to engine
flight conditions.

[0036] In an embodiment with acceleration, three exemplary schedules 302,
304, and 306 are provided on the chart 300. Referring to FIG. 2, the
first acceleration schedule 302 may correspond to the windmill start mode
of steps 220 and 225; the second acceleration schedule 304 may correspond
to the first assisted start mode of steps 230 and 235; and third
acceleration schedule 306 may correspond to the second assisted start
mode of steps 240 and 245. As shown, the first acceleration schedule 302
is more conservative with respect to acceleration rate as compared to the
second and third acceleration schedules 304 and 306, and as such, is
slower. However, as noted above, providing more aggressive acceleration
commands in a scenario that is more appropriate for a windmill start may
result in undesirable issues. The second acceleration schedule 304 is the
relatively most aggressive acceleration schedule. The second acceleration
schedule 304 provides the fastest engine start mode and is typically
appropriate when the starter 140 is at full power to provide the
necessary torque assistance to the engine 110. The third acceleration
schedule 306 is the less aggressive than second acceleration schedule 304
and more aggressive than first acceleration schedule 302. The third
acceleration schedule 306 provides a more moderate or intermediate engine
start mode and is typically appropriate when the starter 140 is at less
than full power, but more than zero power. In one exemplary embodiment,
the third acceleration schedule 306 may be a function of the capability
of the starter 140. In other words, the system 100 and method 200 may
have a number of third acceleration schedules 306 depending on how the
level of capability of the starter 140 and/or the third acceleration
schedules 306 may be an algorithm that calculates the acceleration
commands depending on the level of capability of the starter 140.

[0037]FIG. 4 is a chart 400 depicting exemplary fuel schedules for the
engine system 110 of FIG. 1 in accordance with an exemplary embodiment.
Chart 400 represents the fuel rate command as a function of engine rotor
speed. Three exemplary schedules 402, 404, and 406 are provided on the
chart 400. Referring to FIG. 2, the first fuel schedule 402 may
correspond to the windmill start mode of steps 220 and 225; the second
fuel schedule 404 may correspond to the first assisted start mode of
steps 230 and 235; and the third fuel schedule 406 may correspond to the
second assisted start mode of steps 240 and 245. As such, the fuel
schedules 402, 404, and 406 may respectively correspond to acceleration
schedules 302, 304, 306 discussed above in reference to FIG. 3.

[0038] As shown, the first fuel schedule 402 is more conservative with
respect to fuel rate as compared to the second and third fuel schedules
404 and 406, and as such, may result in a slower start. However, as noted
above, providing more aggressive fuel commands in a scenario that is more
appropriate for a windmill start may result in undesirable issues. The
second fuel schedule 404 is the relatively most aggressive fuel schedule.
The second fuel schedule 404 provides the fastest engine start mode and
is typically appropriate when the starter 140 is at full power to provide
the necessary torque assistance to the engine 110. The third fuel
schedule 406 is the less aggressive than second fuel schedule 404 and
more aggressive than first fuel schedule 402. The third fuel schedule 406
provides a more moderate or intermediate engine start mode and is
typically appropriate when the starter 140 is at less than full power,
but more than zero power. In one exemplary embodiment, the third fuel
schedule 406 may be a function of the capability of the starter 140. In
other words, the system 100 and method 200 may have a number of third
fuel schedules 406 depending on how the level of capability of the
starter 140 and/or the third fuel schedule 406 may be an algorithm that
calculates the fuel commands depending on the level of capability of the
starter 140.

[0039] In general, the method 200 and system 100 enable the most
appropriate selection of start mode, and as such, the most appropriate
selection of fuel and acceleration schedules. Selecting the correct
acceleration and fuel schedules provides improved temperature management,
more efficient start operations, and more efficient fuel usage. The
selection of the appropriate mode is typically performed by the system
100 and method 200 automatically, e.g., without undue decision making on
the part of the pilot. In conventional systems, the pilot may have to
perform numerous steps to evaluate the situation, select a start mode,
and manually initiate the selected start mode. As such, in addition to
providing a more efficient start procedure, the system 100 and method 200
reduce pilot workload and increase situational awareness.

[0040] The turbine engine start-up system and method may be implemented in
wide variety of platforms, such as a computer system that includes a
processor, an interface, a storage device, a bus, and a memory that
stores the start logic as a program. The processor performs the
computation and control functions of the controllers and may include any
type of processor, including integrated circuits such as a microprocessor
implemented on separate systems or as part of an overall vehicle control,
navigation, avionics, communication or diagnostic system. During
operation, the processor executes the programs contained within memory,
which may be any type of suitable memory. The bus serves to transmit
programs, data, status and other information or signals between the
various components of engine system and may include any suitable physical
or logical mechanisms of connecting computer systems and components.

[0041] It should be understood that while the systems and methods are
described in the context of a fully functioning computer system, those
skilled in the art will recognize that the mechanisms of the present
invention are capable of being distributed as a program product in a
variety of forms, and that the present invention applies equally
regardless of the particular type of signal bearing media used to carry
out the distribution. Examples of signal bearing media include:
recordable media such as floppy disks, hard drives, memory cards and
optical disks, and transmission media such as digital and analog
communication links, including wireless communication links.

[0042] Although the systems and methods are described herein as being used
with, for example, an aircraft gas turbine engine, it will be appreciated
that it may be used in numerous other environments including, for
example, space, marine, land, or other vehicle-related applications where
gas turbine engines are used. It will be appreciated that numerous gas
turbine engine configurations and implementations may be used, including
propulsion engines and APUs. For example, the gas turbine engine could be
used to drive one or more rotors of a helicopter, the gas turbine engine
may be implemented as an APU, or the gas turbine engine may be used to
supply power to any one of numerous other types of waterborne, airborne,
or terrestrial vehicles.

[0043] While at least one exemplary embodiment has been presented in the
foregoing detailed description of the invention, it should be appreciated
that a vast number of variations exist. It should also be appreciated
that the exemplary embodiment or exemplary embodiments are only examples,
and are not intended to limit the scope, applicability, or configuration
of the invention in any way. Rather, the foregoing detailed description
will provide those skilled in the art with a convenient road map for
implementing an exemplary embodiment of the invention. It being
understood that various changes may be made in the function and
arrangement of elements described in an exemplary embodiment without
departing from the scope of the invention as set forth in the appended
claims.

Patent applications by Craig E. Thompson, Gilbert, AZ US

Patent applications by Ron Haugland, Scottsdale, AZ US

Patent applications by HONEYWELL INTERNATIONAL INC.

Patent applications in class Ignition or fuel injection after starting

Patent applications in all subclasses Ignition or fuel injection after starting